89 2.9 stumbles on acceleration
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89 2.9 stumbles on acceleration
I have a 89 Bronco II 2.9 fuel injected v-6, when I accelerate it stumbles and falls on it's face. If I let off the gas and slowly add more pedal it will do fine but if you add pedal to fast you will get ahead of it and can feel it start to nose over. You can then let off the gas slightly and try it again as long as you don't get ahead of it. I have run the codes and come up with nothing. I originally had some fault codes replaced defective sensors etc. but have no fault codes at this time. I have checked the fuel pressure it is within range of the bulletin Ken supplied. The engine will not rev up during a WOT(wide open throttle) test either, if stumbles and if you hold the pedal down will just cough and stumbles. Any ideas on where to go from here? Thanks ira551
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I originally had some fault codes replaced defective sensors etc. but have no fault codes at this time.
How thorough of a fuel pressure test did you do? Did you rev the engine while you had the fuel pressure gauge on it to make sure fuel delivery was keeping up with engine demand? Might even be worth the effort to arrange it so you can monitor the fuel pressure under load. Have you checked for raw fuel in the vacuum line to the FPR?
Have you put a vacuum gauge on it to see if the exhaust is plugged?
There are a few ideas, I'm sure others will have different ideas, too.
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Mrshorty we checked the fuel pressure and it held steady at idle and reving the motor. Just replace the FPR and did not have fuel in Vacuum line. Ran vacuum test on engine and is running at 17" of vac and steady.
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The fuel pressure should be 35+ -minimum- and I would go ahead and check the timing with the spout pulled and check for vacuum leaks. The FPR may be -working-, but it sounds as if there is either a vacuum leak, the fuel pump is going out, OR your catalytic converter/exhaust is stopping up.
"How can you -not- notice a man sticking a banana in your tailpipe??" - Beverly Hills Cop
"How can you -not- notice a man sticking a banana in your tailpipe??" - Beverly Hills Cop
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Okay, just checked my timing and vacuum on mine warmed up. Timing with the spout pulled was @ 10 deg BTC with a little slack here and there, but pretty much dead on. Vacuum @ idle was 18-19 inches (which on my gauge is the low end of the "normal" green zone). I manually throttled up with my thumb on the linkage, slight dropoff, but fairly solid response and it shot up to 20-22 inches then steadied around 19-20. If, when you're checking vacuum, and it drops severely (10 inches or less), then you're going to have a lot of work ahead of you because something is blowing by and/or it's time for a new cam/timing chain set. I don't have a "hi-pressure" fuel injection pressure gauge... and I'm not about to try my dial-type air gauge, so, not sure what my fuel pressure is at *shrug*.
I would definitely check to make sure all the intake gaskets are tight and not leaking... and check every vacuum hose for cracks or pinholes, etc. and definitely pull your spout and check your base ignition timing.
I would definitely check to make sure all the intake gaskets are tight and not leaking... and check every vacuum hose for cracks or pinholes, etc. and definitely pull your spout and check your base ignition timing.
Last edited by kernel-panic; Mar 24, 2006 at 06:58 PM.
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reset timing to 10 Deg with spout removed made a big difference. Think I just need to fine tune it. Thanks for all the help..If I run into anything else I'll be beack.
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From: Yokosuka, Honshu, Japan
Originally Posted by ira551
reset timing to 10 Deg with spout removed made a big difference. Think I just need to fine tune it. Thanks for all the help..If I run into anything else I'll be beack.
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